Inhibition of PbO2 formation during lead electrowinning

Ramachandran, Prabhu; Venkateswaran, K.V.; Srinivasan, R.

doi:10.1007/bf00614370

Cited by 3 publications

(3 citation statements)

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“…The effect of certain compounds on the inhibition of Mno 2 formation has been studied using additives such as soluble phosphorous (V) and arsenic (ill) [15]. For the neutralized zinc solution at ph 5, oxidative precipitation using a strong oxidant such as caro's acid and So 2 /o 2 can selectively precipitate manganese as insoluble Mno 2 or Mn(ooh), leaving other impurities, e.g., Mg 2+ , cl − , F − , etc.…”

Section: Introductionmentioning

confidence: 99%

“…in addition, the inhibition of Mno 2 formation by arsenic and phosphorous compounds can be explained on the basis of preferential adsorption of such compounds on the electrode surface [16]. ramachandran et al (1985) studied the addition of phosphoric acid compounds as a deterrent for Mno 2 deposition using galvanostatic technique because of the probable role of these compounds in the inhibition of anodic formation of Mno 2 [19]. The presence of manganese in solution is deterrent for the operation of catalytic anodes since a coating of Mno 2 is formed on the anode surface, which results in reducing catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

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Study on Electrochemical Performance of Dimensionally Stable Anodes during Zinc Electrowinning

Zhang,

Houlachi,

Haskouri

et al. 2023

Archives of Metallurgy and Materials

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Study on ElEctrochEmical PErformancE of dimEnSionally StablE anodES during zinc ElEctrowinningin zinc electrowinning, small amounts of manganese ions additives are needed in the electrolyte to reduce the corrosion of anodes and minimize the contamination of cathodic zinc by dissolved lead. however, excess manganese oxide could cover the dimensionally stable anodes (DSa) surface and decrease their service life. additives of phosphoric acid are put in the electrolyte to complex the manganic Mn 3+ ion and hence reduce its disproportionation to Mno 2 . in the investigation, phosphoric acid was added to sulfuric acid or zinc electrolytes, and conventional and recent electrochemical measurements were carried out to examine electrochemical behaviour of DSa (Ti/iro 2 -Ta 2 o 5 ) anode during zinc electrolysis at 48 ma/cm 2 and 39°c. it was observed that the anodic potentials of DSa anodes were lower by 27 mV after 5 h polarization in the zinc electrolyte containing 35 g/l phosphoric acid at 39°c. Electrochemical impedance measurements show that the addition of 35 ml/l h 3 Po 4 to the zinc electrolyte can increase impedance resistances of the DSa mesh anodes. cyclic voltammogram studies (cV) at a scan rate of 5 mV/s without agitation show that the oxidation peak in the solution with 35 ml/l phosphoric acid addition is highest, followed by that with 17 ml/l phosphoric acid addition and that without addition of phosphoric acid.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Electrochemical Performance of Dimensionally Stable Anodes during Zinc Electrowinning

Zhang,

Houlachi,

Haskouri

et al. 2023

Archives of Metallurgy and Materials

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“…However, it is accompanied by a transfer of chloride ions making the leachate not suitable as the electrolyte for subsequent zinc electrowinning stage due to corrosion problems of aluminum and lead electrodes [19]. This may be overcome by pre-treatment of the ash with sodium carbonate [20], leaching with liquid organic phase containing cation exchanger [21], precipitation of zinc carbonate from the aqueous leachate followed by re-dissolution in sulfuric acid [15], purification of the leachate using ion-exchange resins [18] or application of novel corrosion resistant electrode materials for the electrolysis [22,23]. Alternatively, the zinc ash can be leached with acid chloride solutions, but no detailed procedures for final zinc recovery have been recommended yet.…”

Section: Introductionmentioning

confidence: 99%

Archives of Metallurgy and Materials

Rudnik¹,

Włoch²,

Szatan³

2018

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Oxide fraction of industrial zinc ash from hot dip galvanizing was characterized in terms of composition and leaching behaviour in 10% sulfuric acid solution. Waste product contained about 68% Zn, 6% Cl, 3% Al, 1% Fe, 0.7% Si, 0.5% Pb and minor percentages of other metals (Mn, Cu, Ti etc.). It consisted mainly of zinc oxide contaminated with metallic zinc, zinc hydroxide chloride and silica. Dissolution of the metals from the material was determined as a function of solid to liquid ratio (50-150 kg/m 3 ), temperature (20°C and 35°C) and agitation rate (300 and 900 rpm). The best results (50 g/dm 3 Zn(II) at 78% zinc recovery) were obtained for 100 kg/m 3 and the temperature of 20°C. Increase in the agitation rate had weak effect on the zinc yield. The final solutions were contaminated mainly by Fe(II, III) ions. Leaching of the material was an exothermic process with the reaction heat of about 800 kJ/kg.

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